un·der·ground /ˌʌndɚ/
 地下,地鐵,地道,祕密活動(a.)地下的,祕密的(ad.)在地下,祕密地


 Un·der·ground n.
 1. The place or space beneath the surface of the ground; subterranean space.
    A spirit raised from depth of underground.   --Shak.

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 Un·der·ground, a.
 1. Being below the surface of the ground; as, an underground story or apartment.
 2. Done or occurring out of sight; secret. [Colloq.]
 Underground railroad or Underground railway. See under Railroad.


 Un·der·ground, adv. Beneath the surface of the earth.

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 underground
      adj 1: under the level of the ground; "belowground storage areas";
             "underground caverns" [syn: belowground]
      2: conducted with or marked by hidden aims or methods;
         "clandestine intelligence operations"; "cloak-and-dagger
         activities behind enemy lines"; "hole-and-corner
         intrigue"; "secret missions"; "a secret agent"; "secret
         sales of arms"; "surreptitious mobilization of troops";
         "an undercover investigation"; "underground resistance"
         [syn: clandestine, cloak-and-dagger, hole-and-corner(a),
          hugger-mugger, hush-hush, on the quiet(p), secret,
          surreptitious, undercover]
      3: used of independent armed resistance forces; "guerrilla
         warfare"; "partisan forces" [syn: guerrilla(a), guerilla(a),
          irregular]
      n 1: a secret group organized to overthrow a government or
           occupation force [syn: resistance]
      2: electric underground railway [syn: metro, subway, tube]
      adv 1: in or into hiding or secret operation; "the organization was
             driven underground"
      2: beneath the surface of the earth; "water flowing
         underground"